Reflective optical polarizer device with controlled light distribution and liquid crystal display incorporating the same

Abstract

An optical polarizer device that reflects light of one polarization over a controlled angular range, and improved twisted nematic liquid crystal display devices incorporating the same, is comprised of a grid of conductive elements supported on a textured substrate such that light of one polarization is transmitted through the grid while light of the orthogonal polarization is reflected. The angular distribution of the reflected light is determined by the texture of the substrate. Liquid crystal display embodiments include a configuration intended exclusively for front illumination by ambient light and a configuration which may use either front-illumination or back illumination by an internal light source.

What is claimed is: 
     
       1. A reflective dispersing polarizer device for generally separating a source light beam within the visible or near visible spectrum into two generally orthogonally polarized beams and reflecting a majority of one of the beams in more than one angular orientation, the device comprising: a generally parallel arrangement of a plurality of thin, elongated, spaced-apart elements configured for disposition in the source light beam, spacing of the elements being narrower than the wavelength of visible light and providing means for interacting with electromagnetic waves of the source light beam to generally (i) transmit light having a polarization orientation perpendicular to the elements and defining a transmitted beam of a first polarization, and (ii) reflect light having a polarization orientation parallel with the elements and defining a reflected beam of a second polarization,   each elongated element having an exposed surface that together with the exposed surfaces of the other elements reflect a majority of the light of the second polarization in a diffuse manner.   
     
     
       2. The polarizer device of claim 1, wherein a majority of the exposed surfaces of the elongated elements includes a textured structure configured to diffusely reflect a majority of the light of the second polarization over a range of different angles. 
     
     
       3. The polarizer device of claim 1, wherein a majority of the arrangement of elongated elements share a common general orientation with a reference plane and a common reference axis normal with respect to the reference plane; and wherein the exposed surfaces of the elements form a plurality of component surfaces each having a component axis generally normal with respect to the associated component surface, a plurality of the component axes forming a range of different angles with respect to the common reference axis. 
     
     
       4. The polarizer device of claim 1, wherein a majority of the arrangement of elongated elements share a common general orientation with a reference plane; and wherein the exposed surfaces of the elements form a plurality of component surfaces which are not generally coplanar or parallel with the reference plane. 
     
     
       5. The polarizer device of claim 1, wherein a majority of the exposed surfaces of the elongated elements includes a textured structure comprising a plurality of component surfaces, a majority of the textured structure being formed of component surfaces respectively having a length parallel with the elongated elements which is longer than the wavelength of visible or near visible light. 
     
     
       6. The polarizer device of claim 1, wherein a majority of the exposed surfaces of the elongated elements form a plurality of component surfaces, a majority of the component surfaces respectively having an elevated portion defining a peak and lowered portion defining a valley, each component surface having a size defined by a diameter between opposite sides, the diameter of a substantial number of component surfaces being greater than the wavelength of visible or near visible light. 
     
     
       7. The polarizer device of claim 1, wherein a majority of the elongated elements share a common general orientation with a reference plane; and wherein the exposed surfaces of the elongated elements define a generally wavy cross section taken perpendicular to the reference plane. 
     
     
       8. The polarizer device of claim 7, wherein the cross section is periodic. 
     
     
       9. The polarizer device of claim 7, wherein the cross section is irregular. 
     
     
       10. The polarizer device of claim 7, wherein the wavy cross section is defined by curved surfaces. 
     
     
       11. The polarizer device of claim 7, wherein the wavy cross section is defined by planer surfaces. 
     
     
       12. The polarizer device of claim 7, wherein the wavy cross section is defined by a saw toothed surface. 
     
     
       13. The polarizer device of claim 1, wherein the exposed surfaces of the elongated elements define a plurality of indentations. 
     
     
       14. The polarizer device of claim 13, wherein the indentations are concave. 
     
     
       15. The polarizer device of claim 13, wherein the indentations have planar sides. 
     
     
       16. The polarizer device of claim 1, wherein the exposed surfaces of the elongated elements define a plurality of protrusions. 
     
     
       17. The polarizer device of claim 16, wherein the protrusions are convex. 
     
     
       18. The polarizer device of claim 16, wherein the protrusions have planar sides. 
     
     
       19. A reflective dispersing polarizer device for generally separating a source light beam within the visible or near visible spectrum into two generally orthogonally polarized beams and reflecting a majority of one of the beams in more than one angular orientation, the device comprising: a generally parallel arrangement of a plurality of thin, elongated, spaced-apart elements configured for disposition in the source light beam, spacing of the elements being narrower than the wavelength of visible light and providing means for interacting with electromagnetic waves of the source light beam to generally (i) transmit light having a polarization orientation perpendicular to the elements and defining a transmitted beam of a first polarization, and (ii) reflect light having a polarization orientation parallel with the elements and defining a reflected beam of a second polarization,   each elongated element having an exposed surface that together with the exposed surfaces of the other elements form a plurality of component surfaces which form a textured structure, a majority of the component surfaces respectively having an elevated portion defining a peak and lowered portion defining a valley, each component surface having a diameter, a majority of the textured surface being formed by component surfaces with respective diameters greater than the wavelength of visible or near visible light, to thereby reflect the reflected beam in more than one angular orientation.   
     
     
       20. The polarizer device of claim 19, wherein a majority of the elongated elements share a common general orientation with a reference plane with a reference axis generally normal to the reference plane; and wherein the component surfaces each define a component axis generally normal to the corresponding component surface, the component axes forming a plurality of angles with respect to the reference axis. 
     
     
       21. The polarizer device of claim 19, wherein a majority of the textured structure is formed by component surfaces with respective diameters across the component surface greater than approximately 0.4 microns. 
     
     
       22. The polarizer device of claim 19, wherein the textured structure is defined by a distribution of spatial oscillations with dominant oscillations having a period greater than 0.4 microns. 
     
     
       23. The polarizer device of claim 19, wherein a majority of the textured structure is formed by component surfaces which are generally planar. 
     
     
       24. The polarizer device of claim 19, wherein a majority of the textured structure is defined by component surfaces which are generally convex. 
     
     
       25. The polarizer device of claim 19, wherein a majority of the textured structure is defined by component surfaces which are generally concave. 
     
     
       26. The polarizer device of claim 19, wherein a majority of the textured structure is formed by component surfaces which define a wavy cross section perpendicular to the textured structure. 
     
     
       27. The polarizer device of claim 19, wherein a majority of the textured structure is formed by component surfaces which respectively have a plurality of different elevations with respect to an effective mean height. 
     
     
       28. The polarizer device of claim 19, further comprising a substrate with a textured surface; and wherein the generally parallel arrangement of a plurality of thin, elongated elements is disposed on the textured surface of the substrate, the textured surface of the substrate causing the exposed surfaces of the elongated elements to form the component surfaces. 
     
     
       29. A reflective dispersing polarizer device for generally separating a source light beam within the visible or near visible spectrum into two generally orthogonally polarized beams and reflecting a majority of one of the beams in more than one angular orientation, the device comprising: a substrate configured for disposition in the source light beam and having a surface;   a plurality of generally parallel, thin, elongated, separate elements disposed on the surface of the substrate and spaced apart from one another, each elongated element having an exposed surface that together with the exposed surfaces of the other elements form a plurality of elevational contours with respect to an effective mean height which defines a textured reflective surface, a majority of the textured surface being formed by contours having a length parallel with the elongated elements which is greater than approximately the wavelength of light in the visible or near visible spectrum, spacing of the elements being narrower than the wavelength of visible light and providing means for interacting with electromagnetic waves of the source light beam to generally (i) transmit light having a polarization orientation perpendicular to the elements and defining a transmitted beam of a first polarization, and (ii) reflect light having a polarization orientation parallel with the elements and defining a reflected beam of a second polarization, to thereby direct the reflected beam in more than one angular orientation.   
     
     
       30. The polarizer device of claim 29, wherein a majority of the textured surface is formed by contours with lengths greater than approximately 0.4 microns. 
     
     
       31. The polarizer device of claim 29, wherein the textured surface is defined by a distribution of spatial oscillations with dominant oscillations having a period greater than 0.4 microns. 
     
     
       32. The polarizer device of claim 29, wherein a majority of the textured surface is formed by contours which are generally planar. 
     
     
       33. The polarizer device of claim 29, wherein a majority of the textured surface is formed by contours which are generally convex. 
     
     
       34. The polarizer device of claim 29, wherein a majority of the textured surface is formed by contours which are generally concave. 
     
     
       35. A reflective polarizer device for generally separating a source light beam within the visible or near visible spectrum into two generally orthogonally polarized beams and reflecting a majority of one of the beams in a non-specular manner with respect to a reference plane, the device comprising: a generally parallel arrangement of a plurality of thin, elongated, spaced-apart elements configured for disposition in the source light beam, spacing of the elements being narrower than the wavelength of visible light and providing means for interacting with electromagnetic waves of the source light beam to generally (i) transmit light having a polarization orientation perpendicular to the elements and defining a transmitted beam of a first polarization, and (ii) reflect light having a polarization orientation parallel with the elements and defining a reflected beam of a second polarization,   each elongated element having an exposed surface that together with the exposed surfaces of the other elements form a plurality of component surfaces, a majority of the arrangement of elongated elements sharing a common general orientation with a reference plane and a common reference axis normal with respect to the reference plane, the component surfaces each having a component axis generally normal with respect to the associated component surface, a majority of the component axes having a similar orientation with respect to the reference axis, but a different angular value from the reference axis to reflect a majority of the light of the second polarization in a non-specular manner with respect to the reference plane.   
     
     
       36. The polarizer device of claim 1, wherein the plurality of elements are spaced-apart a distance between approximately 0.005 to 0.2 microns. 
     
     
       37. The polarizer device of claim 5, wherein the length of the component surfaces is between approximately 0.4 to 10 microns. 
     
     
       38. The polarizer device of claim 1, wherein the exposed surfaces of the elements from a plurality of component surfaces, wherein a majority of component surfaces have an elevated portion defining a peak and a lowered portion defining a valley, and wherein at least some of the peaks have different elevations. 
     
     
       39. The polarizer device of claim 1, wherein the exposed surfaces of the elements from a plurality of component surfaces, wherein a majority of component surfaces have an elevated portion defining a peak and a lowered portion defining a valley, and wherein at least some of the valleys have different elevations. 
     
     
       40. The polarizer device of claim 1, wherein the generally parallel arrangement of a plurality of thin, elongated spaced-apart elements comprises a grid of elongated strips of conductive material. 
     
     
       41. The polarizer device of claim 19, wherein the plurality of elements are spaced-apart a distance between approximately 0.005 to 0.2 microns. 
     
     
       42. The polarizer device of claim 29, wherein the plurality of elements are spaced-apart a distance between approximately 0.005 to 0.2 microns. 
     
     
       43. The polarizer device of claim 35, wherein the plurality of elements are spaced-apart a distance between approximately 0.005 to 0.2 microns.